Control of furnace temperature and furnace wall construction



July 25, 1933. F. G. ELY 1,919,324

CONTROL OF FURNACE TEIPERATURE AND FURNACE WALL CONSTRUCTION Filed April30, 1931 3 Sheets-Sheet 3 Fig? 1 INVENTOR BYiIS AT%BNZ F. G. ELY

July 25, 1933.

CONTROL OF FURNACE TEMPERATURE AND FURNACE WALL CONSTRUCTION :5Sheets-Sheet 2 Filed April 50 3 D. Q. 3. L, fl rt l I I I IIIFIIIIIIIIII.

July 25, 1933. F. a. ELY 1,919,324

CONTROL OF FURNACE TEMPERATURE AND FURNACE WALL CONSTRUCTION Filed April30, 1931 3 Sheets-Sheet 5 Fcederic INVENTOR V vention,

Patented July 25, 1933 UNITED" S ATES 1 FREDERIC G. ELY, or camera, NEWJERSEY, Ass'IGNon rANY, or new 11031:, N. Y., A

CORPORATION OF DELAWARE common or FURNACE TEMPERATUR AND summon WALLcons'iutrrcrron Application filed April so,

My invention relates to the control of furnace temperature, especiallyby means of the design and construction of the furnace walls. It relatesparticularly to furnaces,

5 upon the walls of which ash and slag collect.

The invention is useful in connection with furnaces havingwater cooledwalls.

One object of the invention is to. control furnace temperature by thedesign and conlo struction of the furnace walls.

Another object of the, invention is to provide a furnace wallto which.ash and slag will adhere only in limited amounts. A further object isthe provision of such a wall in '15 which ash and slag coated thereonwill have its surface broken up into sections of small area. Otherobjects will become apparent upon consideration of the presentspecification. a

The invention is-shown by way of illustration in the accompanyingdrawings, in which- Figure 1 is a view of the inside surface of afurnace wall comprising tubes with refractory brlck coverlngthe sameFig. 2 is a II II of Figure 1, a I .7 a

Fig. 3 is anelevation of another furnace wall constructed'in accordancewith the in section on the line Fig. 4 is a section on the line IV-IV ofFig. 3, and 4 Fig. 5 is anelevation of a furnace wall showing anotherform of the invention. 7

An important feature ofmodern furnace operation is the control oftemperature within the furnace. The necessity for such tem-' peraturecontrol has-become "more marked with the increased utilization offlu'idfuels 40 and the increasing tendency toward more rapid combustion injthejfurnace. 1

Furnace temperature may be controlled by the construction of the furnacewalls, and various constructions of furnace wall have been used forthispurpose. 'I have discovcred that furnace temperature can" becontrolled by providing on the insides ofthe furnace wallsvaryingproportionsof slight-- lv cooled and highly cooled areas. Theratio ofthe highly cooled surfaces to the slightly 1931. Serial no. 533,73.

ro FULLE LEHIGH ooM-l 7 I have also discovered that a wall soconstructed has another 'valuable property, namely, that of, providing asurface whereon ash and slag will adhere only, in limited quantities. 1v V Where the entire furnace wall is of rough refractory material it hasbeen found that ash and slag in. appreciable quantities will bedeposited upon the walls'by the flame and the combustion gases.Thedeposit covering the walls is not mechanically stable and has beenknown to break away in slabs and fall upon the furnace floor. Where thewalls of the furnace are of the usual construction these slabs arefrequently too heavy and'too large for safe and proper operation of thefurnace. p

According to the present invention, the area ofthe furnace wall isbroken'up so that-the ash or slag coming upon the wall I will notdeposit continuously over the wall, but will be limited in extent tosmall slabs. When thesesmall slabs break away from the walls of. thefurnace and fall into its botins...

tom they will cause a minimumdisturbance because .of their limited.size, and will not interfere with safe operation of the furnace.

In order to accomplish the above result the character of the wallsurface inside of the'furnace is altered-"at intervals,the ratioof'slightly cooledand highly cooledjareas being suchjas to give thedesired.tempera-' hire within the furnace in each case.

In the drawings there is shown afurnace wall of the usual type whichcomprises water cooling tubes 10 and blocks 11 preferably of refractorymaterial covering the tubes on the inside. of the furnace. Thus, theblocks are cooled the water cooled tubes to which they are attached andtheir life is prolonged l in Well known manner.

" The refractory blocks '11 form the major I elements having a differentsurface fromthat part of the interior faceof the wall. Other of therefractory blocks interrupt the Verti cal extent of the blocks 11 inthe/wall and may interrupt the iextent of these blocks in alldirections. These elements may: be

7 means for accelerating heat absorption by the tubes, having a higherrate of heat conductivity than the blocks 11. Thus, in addition to therefractory material carried by the tubes, there is a second class of.material which is of greater heat conducting capacity than the first,and this second class of material may be present in various formsincluding metal blocks or fins on the tubes, the latter beingillustrated in 3 and 4.

In Figs. 1 and 2 the other elements to which referenceis made above, areblocks 12 which interrupt the extent of the refractory blocks 11 formingthe major part'of the interior face of the wall. These blocks 12 have adifferent surface from that of the refractory blocks 11, which surfacemay be that of a "diffe-renttype of refactory or may be ametalsurface,'the entire block 12 being constructed of metal. The blocks 12may i be carried by the tubes as are the refractory blocks 11. In anycase the areas provided. by the blocks 12 are highly cooled and tend tocool the inside of the furnace.

Where the above construction is employed, the ash is deposited on theroughrefractory surfaceof the wall, that is to say-on the refractoryblocks 11, and large areas of deposited ash are prevented from fallingto the furnace floor through the provision at intervals of a surfacehaving a different character; The blocks 12, shown in Figs. .1 and 2,and corresponding elements shown in Figs. 3, 4: and 5, present suchsurfaces of different character, to which the ash or slag will notadhere and over which the ash or-slag will not bridge in a strong enoughsection to make a continuous slab which may fall to the furnace floor.As a result of this construction I only small quantities ofv ash .orslag will 7 fall from the furnace Walls at anytime.

are provided by. tubes 14- having longitudie In Figs. 3 and .4 theinterruptingsurfaces nal fins thereon-and the major part of the Wallisformed by causing refractory 15 to adhere to spiral fin tubes 13.'Obviously,

other means might also be employed for this purpose.

Attention is called toqthe fact that it is not necessary to employ theparticular design shown in Figure 1, but many variations of this designmay be employed with satisfactory effect. As an examplethere isillustrated in Fig. 5 a wall wherein hori zontallines of cleavage onlyare provided.

The particular description here given and I. the forms illustrated inthe-drawings are merely presented by of example. Other constructionsvarying in detail but not in principle from'the invention. willnaturally suggest themselves to those dealing with this problem."

I claimi s 1. In a ,furnace'for burning slag-forming fuel, a wallcomprising water tubes, refrac tory material carried by po'rtions ofsaid tubes, and other portions of said tubes arranged to absorb heatmore directly than the firstmentioned portions, said portlons belngarranged alternately throughout substantialiythe'entire Wall surface toprovide slightly f cooied and highly cooled areas to regulate furnacetemperature and prevent accumulation of largqmasses of. slag.

in a, furnace for burnlng slag-forming fuel, a wall comprisingwater'tubes, refractory materials carried by portions of said tubes, andother portions of'saidtubes arranged to absorb heat more directly thanthe first mentioned portions, said portions being hrran ged alternatelythroughout substantially the entire Wall surface in both vertical andhorizontal. directions to provide slightly cooledand highly cooled areasto regulate furnace temperature and prevent accumulation of large massesof slag.

8. In a furnace for burning slagforming fuel, a wall comprising watertubes, refractory blocks carried by portions'of said tubes,

and other portions of said tubes arranged to' absorb heat more directlythan'the first men-v series of means on other portions of said tubes formore directly absorbing heat, said blocks and said means being disposedand arranged to provide a series of alternate slightly cooled and highlycooled areas throughout substantially the entire wall surface toregulate furnace temperature and prevent accumulat on of large masses offuel residues such as slag or ash.

5. In a furnace for burning slag-forming fuel, a Wall comprising Watertubes, refractory material carried by portions of some of said tubes,and a second class of material carried by other tubes and tube portions,said second class of material being of greater heat conducting capacitythan said refractory material, and said materials being arrangedalternately throughout substantially the entire wall surface to provideslightly coolcd and i highly cooled areas to regulate furnace temperature and prevent accumulation-of large masses of fuel residues suchas slag or ash.

'6; "a furnace for burning slag-formingfuel, a wall comprising Watertubes," refractory' material carriedby portions of some of said tubes,and a second class ofmaterial 7 carried by-other tubes and tubeportions, said said bare metal being arranged alternately 1 throughoutsubstantially the entire Wall surface to provide slightly'cooled andhighly cooled areas to regulate furnace temperature andpreventaccumulation of large areas of fuel residues-such as slag 0r ash.

8. In a furnace for burning slag-forming fuel, a Wall comprising Watertubes, refractory material'c-arried by port-ions of some of said tubes,and bare metal on other tubes and tube portions, said refractorymaterial and said bare metal beingarranged alternately throughoutsubstantially the entire Wall surface 1 in both vertical and horizontaldirections to provideslightly cooled and highly cooled areas to regulatefurnace temperature and preventaccumulation of large areas of fuelresidues such as slag brash.

' FREDERIO G. ELY.

